/*
 * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
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 *
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 *
 *
 *
 *
 *
 */
package javax.swing.plaf.nimbus;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.Insets;

/**
 * ImageScalingHelper
 *
 * @author Created by Jasper Potts (Aug 8, 2007)
 */
class ImageScalingHelper {

  /**
   * Enumeration for the types of painting this class can handle.
   */
  enum PaintType {
    /**
     * Painting type indicating the image should be centered in the space provided.  When used the
     * <code>mask</code> is ignored.
     */
    CENTER,

    /**
     * Painting type indicating the image should be tiled across the specified width and height.
     * When used the <code>mask</code> is ignored.
     */
    TILE,

    /**
     * Painting type indicating the image should be split into nine regions with the top, left,
     * bottom and right areas stretched.
     */
    PAINT9_STRETCH,

    /**
     * Painting type indicating the image should be split into nine regions with the top, left,
     * bottom and right areas tiled.
     */
    PAINT9_TILE
  }

  ;

  private static final Insets EMPTY_INSETS = new Insets(0, 0, 0, 0);

  static final int PAINT_TOP_LEFT = 1;
  static final int PAINT_TOP = 2;
  static final int PAINT_TOP_RIGHT = 4;
  static final int PAINT_LEFT = 8;
  static final int PAINT_CENTER = 16;
  static final int PAINT_RIGHT = 32;
  static final int PAINT_BOTTOM_RIGHT = 64;
  static final int PAINT_BOTTOM = 128;
  static final int PAINT_BOTTOM_LEFT = 256;
  /**
   * Specifies that all regions should be painted.  If this is set any other regions specified will
   * not be painted. For example PAINT_ALL | PAINT_CENTER will paint all but the center.
   */
  static final int PAINT_ALL = 512;

  /**
   * Paints using the algorightm specified by <code>paintType</code>.
   *
   * @param g Graphics to render to
   * @param x X-coordinate
   * @param y Y-coordinate
   * @param w Width to render to
   * @param h Height to render to
   * @param image Image to render from, if <code>null</code> this method will do nothing
   * @param sInsets Insets specifying the portion of the image that will be stretched or tiled, if
   * <code>null</code> empty <code>Insets</code> will be used.
   * @param dInsets Destination insets specifying the portion of the image will be stretched or
   * tiled, if <code>null</code> empty <code>Insets</code> will be used.
   * @param paintType Specifies what type of algorithm to use in painting
   * @param mask Specifies portion of image to render, if <code>PAINT_ALL</code> is specified, any
   * other regions specified will not be painted, for example PAINT_ALL | PAINT_CENTER paints
   * everything but the center.
   */
  public static void paint(Graphics g, int x, int y, int w, int h,
      Image image, Insets sInsets,
      Insets dInsets, PaintType paintType, int mask) {
    if (image == null || image.getWidth(null) <= 0 || image.getHeight(null) <= 0) {
      return;
    }
    if (sInsets == null) {
      sInsets = EMPTY_INSETS;
    }
    if (dInsets == null) {
      dInsets = EMPTY_INSETS;
    }
    int iw = image.getWidth(null);
    int ih = image.getHeight(null);

    if (paintType == PaintType.CENTER) {
      // Center the image
      g.drawImage(image, x + (w - iw) / 2,
          y + (h - ih) / 2, null);
    } else if (paintType == PaintType.TILE) {
      // Tile the image
      int lastIY = 0;
      for (int yCounter = y, maxY = y + h; yCounter < maxY;
          yCounter += (ih - lastIY), lastIY = 0) {
        int lastIX = 0;
        for (int xCounter = x, maxX = x + w; xCounter < maxX;
            xCounter += (iw - lastIX), lastIX = 0) {
          int dx2 = Math.min(maxX, xCounter + iw - lastIX);
          int dy2 = Math.min(maxY, yCounter + ih - lastIY);
          g.drawImage(image, xCounter, yCounter, dx2, dy2,
              lastIX, lastIY, lastIX + dx2 - xCounter,
              lastIY + dy2 - yCounter, null);
        }
      }
    } else {
      int st = sInsets.top;
      int sl = sInsets.left;
      int sb = sInsets.bottom;
      int sr = sInsets.right;

      int dt = dInsets.top;
      int dl = dInsets.left;
      int db = dInsets.bottom;
      int dr = dInsets.right;

      // Constrain the insets to the size of the image
      if (st + sb > ih) {
        db = dt = sb = st = Math.max(0, ih / 2);
      }
      if (sl + sr > iw) {
        dl = dr = sl = sr = Math.max(0, iw / 2);
      }

      // Constrain the insets to the size of the region we're painting
      // in.
      if (dt + db > h) {
        dt = db = Math.max(0, h / 2 - 1);
      }
      if (dl + dr > w) {
        dl = dr = Math.max(0, w / 2 - 1);
      }

      boolean stretch = (paintType == PaintType.PAINT9_STRETCH);
      if ((mask & PAINT_ALL) != 0) {
        mask = (PAINT_ALL - 1) & ~mask;
      }

      if ((mask & PAINT_LEFT) != 0) {
        drawChunk(image, g, stretch, x, y + dt, x + dl, y + h - db,
            0, st, sl, ih - sb, false);
      }
      if ((mask & PAINT_TOP_LEFT) != 0) {
        drawImage(image, g, x, y, x + dl, y + dt,
            0, 0, sl, st);
      }
      if ((mask & PAINT_TOP) != 0) {
        drawChunk(image, g, stretch, x + dl, y, x + w - dr, y + dt,
            sl, 0, iw - sr, st, true);
      }
      if ((mask & PAINT_TOP_RIGHT) != 0) {
        drawImage(image, g, x + w - dr, y, x + w, y + dt,
            iw - sr, 0, iw, st);
      }
      if ((mask & PAINT_RIGHT) != 0) {
        drawChunk(image, g, stretch,
            x + w - dr, y + dt, x + w, y + h - db,
            iw - sr, st, iw, ih - sb, false);
      }
      if ((mask & PAINT_BOTTOM_RIGHT) != 0) {
        drawImage(image, g, x + w - dr, y + h - db, x + w, y + h,
            iw - sr, ih - sb, iw, ih);
      }
      if ((mask & PAINT_BOTTOM) != 0) {
        drawChunk(image, g, stretch,
            x + dl, y + h - db, x + w - dr, y + h,
            sl, ih - sb, iw - sr, ih, true);
      }
      if ((mask & PAINT_BOTTOM_LEFT) != 0) {
        drawImage(image, g, x, y + h - db, x + dl, y + h,
            0, ih - sb, sl, ih);
      }
      if ((mask & PAINT_CENTER) != 0) {
        drawImage(image, g, x + dl, y + dt, x + w - dr, y + h - db,
            sl, st, iw - sr, ih - sb);
      }
    }
  }

  /**
   * Draws a portion of an image, stretched or tiled.
   *
   * @param image Image to render.
   * @param g Graphics to render to
   * @param stretch Whether the image should be stretched or timed in the provided space.
   * @param dx1 X origin to draw to
   * @param dy1 Y origin to draw to
   * @param dx2 End x location to draw to
   * @param dy2 End y location to draw to
   * @param sx1 X origin to draw from
   * @param sy1 Y origin to draw from
   * @param sx2 Max x location to draw from
   * @param sy2 Max y location to draw from
   * @param xDirection Used if the image is not stretched. If true it indicates the image should be
   * tiled along the x axis.
   */
  private static void drawChunk(Image image, Graphics g, boolean stretch,
      int dx1, int dy1, int dx2, int dy2, int sx1,
      int sy1, int sx2, int sy2,
      boolean xDirection) {
    if (dx2 - dx1 <= 0 || dy2 - dy1 <= 0 || sx2 - sx1 <= 0 ||
        sy2 - sy1 <= 0) {
      // Bogus location, nothing to paint
      return;
    }
    if (stretch) {
      g.drawImage(image, dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2, null);
    } else {
      int xSize = sx2 - sx1;
      int ySize = sy2 - sy1;
      int deltaX;
      int deltaY;

      if (xDirection) {
        deltaX = xSize;
        deltaY = 0;
      } else {
        deltaX = 0;
        deltaY = ySize;
      }
      while (dx1 < dx2 && dy1 < dy2) {
        int newDX2 = Math.min(dx2, dx1 + xSize);
        int newDY2 = Math.min(dy2, dy1 + ySize);

        g.drawImage(image, dx1, dy1, newDX2, newDY2,
            sx1, sy1, sx1 + newDX2 - dx1,
            sy1 + newDY2 - dy1, null);
        dx1 += deltaX;
        dy1 += deltaY;
      }
    }
  }

  private static void drawImage(Image image, Graphics g,
      int dx1, int dy1, int dx2, int dy2, int sx1,
      int sy1, int sx2, int sy2) {
    // PENDING: is this necessary, will G2D do it for me?
    if (dx2 - dx1 <= 0 || dy2 - dy1 <= 0 || sx2 - sx1 <= 0 ||
        sy2 - sy1 <= 0) {
      // Bogus location, nothing to paint
      return;
    }
    g.drawImage(image, dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2, null);
  }


}
